Chill mat for ingot molds and method of making same



Jan. 26, 1960 2,922,206 w. E. SCHMERTZ CHILL MAT FOR INGOT MOLDS AND METHOD OF MAKING SAME Filed Sept. 23, 1957 g 3 INVENTOR.

WILLIAM E. SCHMERTZ. BY M, M rm ATTORNEYS.

Un edSw Q ,92 I CHILL MAT FOR INGOT MOLDSAND METHOD 1 OF MAKING SAME William E. Schmertz, Pittsburgh, Pa. i I Application September 23, 1957, Serial No.685,59 1

9 Claims. (Cl; 22-139) This invention is for an insert to be placed in the bottom of an ingot mold before the molten metal is poured into the mold, such inserts being known as chill mats, and for a process of manufacturing same.

Chill mats are commonly formed by coiling one or more continuous strips into a mat. One successful form of mat is disclosed in my Patent No. 2,463,643, dated November 9, 1948, wherein two strips, one corrugated and one flat, are coiled together so that the convolutions of flat and corrugated metal alternate. One advantage of corrugating is to provide a surface having many openings that tend to break the wash or splash of the metal when it is first poured, while another advantage is to reduce the weight of metal, which is relatively expensive. This is quite a factor because themats are most extensively used in making alloy or stainless steel and desirably has the same, or nearly the same analysis.

Stainless steel is often sold or prepared for use in sheets of a standard size, and in the preparation of such sheet a large aggregate tonnage of end or edge trimmings ranging in length from four to eight feet, and in width from perhaps a half inch to two inches, are produced. While this material has some value as melting scrap, it is not prime material for this purpose and the high cost of handling it for scrap further reduces its value, or the price for which it can be disposed.

The present invention has for its primary object to utilize such waste material in a chill mat and at the same time provide a superior mat, and which has the incidental advantage to the user of converting the scrap into good melting scrap.

A further object of the invention is to provide a method of improving the mat for its intended purpose, reducing its cost, and utilizing short lengths of scrap.

According to this invention a mat is prepared by using one continuous band of steel which may be either flat or corrugated, and winding it under tension into a coil.

As the coil is wound, lapped short strips of metal advantageously of varying widths are fed into the bight where the continuous strip is forming a convolution of the coil. The mat so produced has a relatively few convolutions of the expensive preformed continuous strip separated by multiple layers of scrap strip, much of which is wider than the continuous band, while gaps exist between the end-to-end spacing of individual short strips. The result is that while one surface of the mat is relatively fiat, the other surface which would be the top surface, has channels of varying depths and openings which retard splash and the wash of the molten metal. The mat is comprised principally of such scrap but it is firmly bound in place by the continuous band. After the mat is used, it forms a part of the ingot that is cropped and remelted, so that by using the waste pieces in this way, the waste is converted to good melting scrap 'in an advantageous and economical way. The finished mat, after being rolled, is banded by a flat band of steel passed around it and the outer convolutions are also welded, the band keeping the mat from coning at the center, the

2 band and the weld holding it from unwinding, these steps of handing and welding being usual in the art.

My invention may be more fully understoodby reference to the accompanying drawings, in which:

Fig.1 is a somewhat schematic perspective view showing a method of and apparatus for making the mat;

Fig. 2 is a fragmentary plan view of a mat embodying my invention; and

Fig. 3 indicates the nature of a section through a mat, no two mats however, being likely to be the same.

In the drawings, 2 designates a disk on a shaft 3 which is designed to be revolved slowly by a motor (not shown), apparatus of this type being well known. On the front face of the disk there is a core 4 of the type usually used, to which the starting end of a continuous band of metal is attached for winding the mat. This continuous band, designated 5, may be either flat or corrugated, but for simplification has been shown flat. It is delivered from acoil 6- on a reel (not shown) that exerts some drag to hold the strip under tension, this being well knownin the art.

At a proper level and spaced from the disk 2 I provide a-horizontal shelf 7 with a vertical guide wall 8 along one-edge, and of a length to hold the longest strip of scrap that would normally be used. The vertical guide wall is preferable in the plane of the disk 2.

In operation the disk is revolved to wind the continuous strip 5 into a coil, and as the winding proceeds the operator takes pieces of waste strip of the kind de-. scribed at random from a convenient pile and lays them. in overlapping relation on the shelf 7, pushing one edge against the guide 8. While Fig. 1 for purpose of clarity of illustration indicates these pieces of scrap, designated 9, as being of uniform width, as indeed they may be, they are apt to range between one-half inch and two inches. Wider pieces are preferably not used as they may make the mat unstable, introduce stacking or handling problems, and be too high in the ingot mold and can be advantageously used for other purposes. Little of the waste is narrower than a half inch. There may even be different gauges of metal in the same batch, and this is not objectionable, because by lapping one piece on another there is adequate pressure to bind strips of different gauge in the same mat.

As the operator arranges the strips on the shelf he pushes them or fecds them into the bight under the con- \olution being formed by the continuous band. Depending on the gauge of scrap, there may be as many as four plies of it, and always preferably two, except perhaps where the leading end of one strip may be spaced from the trailing end of the preceding one to form an opening through the completed mat.

By having the guide 8 in the plane of the disk, one edge of each strip 9 will be in the same plane and lie against the face of the disk during forming, so that the mat will be fiat on one face, while the other will be irregular, channeled, and uneven. No two mats are likely to be identical, but will be of adequate overall uniformity for their intended purpose.

In Figs. 2 and 3 the continuous band, designated 5, is corrugated, but as stated above, need not be, although it is advantageous. The irregular pieces between the convolutions 5 are designated 9. The final band which is put above the mat is not shown. When the mat is formed to the desired diameter, about twelve inches being usual, a tack weld of the outermost convolutions is made to hold the coil from unwinding.

If desired the operator may use narrower scrap in the center convolutions and wider in the outer part, so that the top of the mat will be roughly dished or cupped, but this requires more sorting of the scrap, but for some purposes may be desired.

The resulting mat is an improvement over existing mats not only because of its economy, but because'it has an uneven surface, a large mass of metal to freeze the molten metal that strikes it, and slit-like openings through it. With'one surface flat, it makes good thernfialcoi1"- tact with themold stool or bottom.

I claim: V w t I 1. An ingot mold insert mat comprising a conti'nuous strip of metal coiled upon itself from the center outwardly, and short strips .of metal in overlapping nd t'o end relation confined between the convolutions of' said coil.

2. An ingot mold insert mat as defined 'i'n'claim "l in which the continuous metal strip isofuniform widthand the short lengths are of varying widths.

3. An ingot mold insert mat as defined in claim 2 in which the edges of all of the strips on one side of the mat are substantially in a plan: forming a 'flatbottom for the mat.

4. An ingot mold insert mat comprising a long ribbon of metal coiled into a spiral and short overlapping strips of metal arranged at random between the convolutions of the spiral and separating the, convolutions one-from another. g

5. An ingot mold insert mat as defined in claim 4'in which there are usually at least two plies of short'strips between the convolutions of the continuous strip and wherein some of the short strips are in spaced end-toend relation while others have their ends in overlapping relation whereby openings are provided Where the strip ends are so spaced. I

6. The method of forming an ingot mold insert mat which comprises winding a continuous strip of'm'e'tal-into a spiral, introducing short strips lengthwise of the first strip of metal between the convolutions of the strip with the ends of the short strips being in overlapping relation being coiled between the convolutions of the continuous strip to confine the short strips between the convolutions of the continuous strip and substantially concentric with the center about which the continuous strip is coiled, and fastening the outer end of the continuous strip to secure it against unwinding.

7. The method as defined in claim 6 in which the short strips are overlapped so that there are a plurality of metal thicknesses formed by the short strips between the convolutions of thecontinuous strip.

8. The method defined in claim 6 in which said winding is effected against a supporting disk and the short strips are introduced into the convolutions with one edge of the continuous strip and one edge of the short strip supported by the disk.

9. The method of making an ingot mold insert mat which comprises arranging short strips of metal upon a support with one strip overlying another and with the ends of the strip -'in staggered relation and feeding the strips so arranged lengthwise between the convolutions of a continuous strip of metal being formed into a 'coil about a central arbor.

References Cited in'thefile of this patent UNITED STATES PATENTS 1,457,763 Adams June 5, 1923 2,154,918 Hendley NOV. 1, 1938 "2,453,643 Schmertz Nov. 9, 1948 2,472,603 Mayer June 7, 1949 2,743,493 Schmertz May 1, 1956 2,763,906 Sterick Sept. 25, 1956 2,807,846 Sterick Oct. 1, 1957 ambit 

